The present invention related to devices for dispensing, administering, injecting or delivering substances, and to methods of making and using such devices. More particularly, it relates to devices for dispensing a substance, such as injection devices or injection pens, having a dose setting element for administering a set or selected dose of an injectable product. In some embodiments, such injection devices may be used for self-administering a product, may be disposable, and/or may be used with a single or dual chamber ampoule.
Relatively small, easily portable injection devices, which may be referred to as injection pens, are commonly used as a means of self-administering medicaments. Ease of use, accurate dose metering and reliability of the dose setting are important factors for self-administering medicaments, such as insulin or a hormone.
Patent specification DE 10 2004 310, owned by the owner of the present application, discloses an injection device with a dose metering element, which effects a forward drive movement relative to the housing of the injection device in a forward drive direction and a dose metering movement opposite the forward drive direction. The dose metering element is coupled with a conveying mechanism so that the forward drive movement causes a conveying movement of the conveying mechanism. The length of a travel distance determining the dose to be dispensed which the dose metering element covers during the forward drive movement is set by the dose metering movement. The housing constitutes a first catch mechanism in a sleeve portion surrounding the dose metering element and a second catch mechanism formed by the dose metering element or a separate, additional dose metering catch body, and a catch engagement of the catch mechanisms can be released by a dose metering movement of the dose metering element or the separate, additional dose metering body without any rotating motion.
Patent specification U.S. Pat. No. 5,807,346 discloses a measuring instrument for dispensing different doses of a fluid, which has a reservoir for accommodating the fluid, a displaceable toothed rack element axially disposed inside and a pushing element which can be operated by the user. Annular notches are provided on the toothed rack element, and the housing has various axial slots distributed across its periphery. An outwardly projecting pin is provided on the pushing element, which is able to engage in one of the axial slots of the housing, thereby enabling the setting element to be easily extracted by the user.
Patent specification EP 0 713 403 B1 discloses a syringe with a barrel, which defines or has a cylinder. The cylinder has a nozzle at one end and encloses a plunger able to slide in the longitudinal direction inside the cylinder. The distance by which the plunger is able to move inside the cylinder defines the volume administered by the syringe, and the plunger is drivingly coupled with a slide so that it moves parallel with the plunger. The longitudinal distance by which the plunger is able to slide inside the cylinder is defined by restrictions to the movement caused by a stop surface on the barrel or on the slide co-operating with end stops on the slide or barrel. The syringe can be locked in a state in which the stop surface and the end stops are able to move relative to one another within movement restrictions which can be selected from one or more selectable, pre-defined movement restrictions. Because the stop surface has an insert which can be inserted in an orifice in the barrel or slide so that it projects out from it and can only be removed with great difficulty or by using a special tool, the projecting part of the insert acts as a stop surface. The position of each such orifice relative to the end stops defines one of the pre-selected movement distances.